This invention relates in general to locks and deals more particularly with improved cam locks of the type used on vending machines, coin boxes, panel boxes, office furniture and the like. Such a lock usually has a generally cylindrical shell, a rotary key plug supported within the shell, and a cam mounted on the inner end of the key plug and adapted for locking engagement with an associated strike or keeper. In accordance with accepted standards for such cam locks, the shell usually has a 3/4 inch outside diameter and is threaded to receive a retaining nut used in mounting the lock. The requirements of a particular lock installation may impose further limitation on the axial length of the shell. Conventional pin tumbler, disc tumbler or side bar locking mechanism are usually utilized in such a lock and affords moderate security. While various other locking mechanisms are available which offer higher degrees of security, such locking mechanisms are not usually found in cam locks of the aforedescribed type, because of spatial limitations within the plug and shell. Heretofore, at least one cam lock has been provided which offers a higher degree of security than previously attainable with the aforementioned well known conventional locking mechanisms. This lock, illustrated and described in U.S. Pat. No. 3,499,302 to Spain et al, utilizes pin tumblers which are raised, lowered and axially rotated to release a fence or side bar, and may be best characterized as an improved side bar lock.
It is the general aim of the present invention to provide improved cam locks of high security type of simple construction and having locking members which consist solely of pin tumbler assemblies.